<!-- based on issue 13 -->
<h1><a href="1">one</a></h1>
<h2><a href="2"> two </a></h2>
<h3><a href=" 3 "> three </a></h3>
<h4><a href="4">four</a> <a href="5"> five </a></h4>
<p>
  <a href="6"> six </a> <a href="7"> seven eight </a> <a href="9">nine</a> <a></a>
  <a href="#"> </a> <a href="10"> ten </a> foo<a href="11"> eleven </a>
</p>